Tube bending machines



p 1959 s. WlLMAN 2,901,930

TUBE BEINDING MACHINES Filed Sept. 16, 1954 6 Sheets-Sheet 1 ATT RNEYSSept. 1, 1959 s. WILMAN 2,901,930

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P 1959 s. WILMAN 2,901,930

TUBE BENDING MACHINES Filed Sept. 16, 1954 6 Sheets-Sheet 6 INVEN TORSIGISMO/VD W/LMAN United States Patent Of'ice TUBE BENDING MACHINESSigismund Wilman, Courbevoie, France Application September 16, 1954,Serial No. 456,508

Claims priority, application France August 10, 1954 8 Claims. (Cl.80--11) In French Patent No. 1,016,517, filed on April 20, 1950, thereis described a method of and a machine for the cold bending of tubulararticles whereby the wall thickness of the tube to be bent is reduced inthe region of the outer arc of the bent portion without appreciablycompressing the side forming the inner arc.

This former patent describes a machine for carrying out the rollingoperation which comprises a rolling-ball or rolling-wheel device adaptedto be introduced into the tube to be rolled.

This machine offered a few drawbacks, notably in that the rolling ballsor wheels had a small diameter in comparison with the rolling depth, sothat the tube metal was caused to creep along a circular arc describedby the rolling device and that the tubes were not bent according to apredetermined plane but were more or less spiraled or twisted. Moreover,the means provided in the aforesaid machine for adjusting the rollingdepth was rather rudimentary and when it was contemplated to alter thethrow of the device or to change the rolling radius, the operator wascompelled to stop the machine to carry out the necessary adjustments,which involved a substantial loss of time and a poor machine output.

It is the chief object of the present invention to overcome thesedrawbacks by providing a machine having an article rolling operationusing a single rolling-wheel of relatively large diameter with respectto the rolling depths. In fact, this diameter is greater than half theinner diameter of the tube to be rolled. With this novel arrangement thetube metal is not forced in a direction following the rolling arc sincethe rolling-wheel engages 'the metal with a very small angle. makes itpossible to bend tubular articles in a predetermined plane without anyspiralling or twisting thereof.

Furthermore, the machine according to this invention comprises twodifferent adjustment means adapted to be operated either in unison orseparately, i.e.: firstly, for adjusting the length of the rollingradius, and secondly for adjusting the position of the center of thisrolling radius.

Finally, additional means are also provided in this machine whereby theadjustments indicated in the preceding paragraph may be carried out atwill when the machine is in motion, without stopping it for altering theradius of curvature, thereby permitting a substantial increase in theefficiency of the machine.

Thus, this machine In order to afford a clearer understanding of theinplished by the machine illustrated in the other figures;

Figures 2 and 3 are a longitudinal axial section and a 2,901,930Patented Sept. 1, 1959 cross-section, respectively, the latter beingtaken upon the line aa of Figure 2, showing the parts employed forrolling the tubular article 1 internally in view of bending same;

Figures 4 and 5 are a longitudinal axial section and a. cross-section,the latter being taken upon the line b-b of Figure 4, showing themechanisms provided for effecting the aforesaid two adjustments;

Figure 6 is a cross-sectional view taken upon the line c--c of Figure 7showing the carriage arrangement;

Figure 7 is a substantially complete view of the machine with partsshown in axial section; and

Figure 8 is a perspective view of the machine.

Referring now to the drawings, Figure 1 illustrates diagrammatically atubular article 1 undergoing a bending operation by rolling in a machineconstructed according to the teachings of this invention. Before therolling operation the tube axis is located at centre 2. The tube isrolled along an offset circle by the rolling-wheel 3 rotating about itsaxis 4-, the latter describing in turn a circular path 5 around therolling axis 6. Therefore, the outer end of the radius 7 extending fromthe axis 6 will describe a circular path 8 representing the roller innersurface. This circle is offset with respect to the circle 10representing the inner surface of the tube before the rolling operation,the radius of this surface being indicated at 9.

Under these conditions, the axes passing through the centers 2 and 6 liein the plane of curvature of the bent tube; in other words, if it isdesired to thin out the tube wall on the side of greater radius of thebent portion without interfering with the radius of the opposed or innerside, both centers 2 and 6 will be located on the tube diameter passingthrough points 11 and 12, of which the former indicates the place whereno rolling action is exerted on the tube wall while the other indicatesthe point of maximum rolling depth.

It is apparent from Figure 1 that under these conditions the distancefrom center 2 to center 6 is one-half of the rolling depth. To ensure aproper bending action it is necessary that the rolling action producedat point 11 be zero or substantially zero; in other words, the circularpath 8 described by the outer end of radius 7 extending from center 6,and the circular path 10 described by the outer end of radius 9extending from center 2 should be tangent or substantially tangent toeach other at the theoretically stationary and unrolled point 11. In thefirst instance the unrolled portion if observed in the longitudinaldirection will be a continuous line and in the other case a more or lesswide surface.

To modify the rolling depth it is necessary to alter the distancebetween the centers 2 and 6; since the former is fixed this change canonly be achieved by displacing the center -6 along the line 11-12. Thisdisplacement may be effected by means of any suitable mechanism, forexample an eccentric motion.

If point 6 is lowered to increase the rolling depth at point 12, all thepoints positioned along the circle 8 will be lowered and therefore thiscircle will not be tangent to the initial circle 10 at point 11. In thiscase the unrolled strip left inside the bent tube will be too wide andif its width is equal to or greater than a quarter circle, the tube willbe ovalized. Another drawback will be observed in the opposed directionif the point 6 is raised instead of being lowered. In this case, therolling depth will be reduced at point 12 and increased at point 11without any beneficial result.

The machine described herein by way of example and shown in theaccompanying drawings is provided with adjustment means of the eccentrictype, but the corre sponding adjustments may also be made through anyother suitable mechanical means.

In Figures 2 and 3 of the drawings there is shown the rolling devicewith the relevant adjusting eccentric members. The rolling-wheel 3 isrotatably mounted for loose rotation on one end of a stub-shaft 13around its axis 4, suitable bearing means, for example a needle-bearing14, being interposed between the rolling-wheel 3 and stubshaft 13. Thisstub-shaft 13 is secured by means of a bolt 15 on one end of a mainshaft 16 mounted for rotation about its axis 6 offset with respect tothe axis 2 of the tubular article 1 to be bent. The rotary assembly issupported by a needle-bearing 17 for rotation inside a stationary memberguided by a mandrel 18 corresponding in size to the inner surface of thestill non-machined portion of tube 1 and engaging the latter with aclearance sufficient to enable the tube to engage the mandrel with theminimum resistance. The tube 1 is inserted between the stationary guidemembers 19, 20 forming together a rolling support.

For altering the position of center 6 relative to center 2 along theline 11--12 of Figure 1 a pair of eccentric sleeve members 21 and 22positioned between the bearing 17 and mandrel 18 and adapted to rotateonly in opposed directions are used, so that when these eccentricmembers are rotated the center 6 will be displaced vertically along theaforesaid line 11-12. In fact, if only one eccentric sleeve wereprovided, the axis 6 would not follow a rectilinear, vertical path but acircular path around the axis 2, and the point 12 of maximum rollingdepth would be moved sidewise and the rolled tube spiralled or twistedas in the case of the aforesaid known machines.

Of course, the transverse displacement of the axis 6 is not attended bya similar displacement of the main shaft 16 throughout its length, asthe opposite end of this shaft will not be moved in a direction acrossits axis. Nevertheless, the displacement of the rolling center, i.e.axis 6, is permitted by the relatively great length of the main shaft16.

Figure 3 illustrates in cross-section the eccentric sleeves 21 and 22 inthe positions corresponding to a relatively shallow rolling of athin-walled tubular article. When the tube to be bent by rolling has arelatively thick wall it is necessary to carry out the rolling operationat a greater depth and therefore to rotate the eccentric sleeves 21, 22to a greater extent in relation to each other.

The rolling radius 7 may be adjusted by rotating another or innermosteccentric sleeve 23 fitted around the rolling-wheel carrying stub-shaft13 and surrounded in turn by the needle-bearing 17. By rotating thisinner eccentric sleeve 23 relative to the parts 13, 14, 15, 16 of whichit normally follows the rotational movements, it is possible to adjustthe distance between centers 4 and 6, and to modify correspondingly therolling radius. With this arrangement it is also possible to suppressthe rolling action completely, for example when it is desired to passprogressively from a bent portion to a straight or unrolled portion ofthe tube, and to resume the rolling action at another point of the tubefor forming another bend at a predetermined interval.

The eccentric sleeves 21, 22, 23 are controlled and rotate through amechanism described hereafter and shown in longitudinal axial section inFigure 4 and in cross-section in Figure 5.

A case consisting essentially of two half-shells 28, 29 encloses theeccentric-sleeve adjusting device. This device is adapted notably toensure the vertical displacement of the rolling circle 8 with respect tothe tube center 2; for this purpose, the pair of eccentric sleeves 21,22 are connected fast to tubular shafts 31, 32 respectively; on theirends opposed to those engaged by the eccentric sleeves these tubularshafts 31, 32 carry for rotation therewith bevel wheels 33, 34,respectively, as shown.

Both bevel wheels 33, 34 are in constant meshing engagement with anintermediate bevel pinion 35 rotating about a fixed axis; when. thispinion is rotated it causes 4 the bevel wheels 33, 34 which are of samesize, to rotate at the same angular velocity but in opposed directions.

The bevel pinion 35 is rigid with a co-axial worm wheel 36 in constantmeshing engagement with a worm 37 adapted to be actuated by a handwheel84 (Figure 8).

As already pointed out hereinabove the inner eccentric sleeve 23 ismovable about the rolling-wheel stub-shaft 13 and rigidly connected witha tubular transmission shaft 38 surrounding the main shaft 16. Aball-bearing or set of ball-bearings 39 are fitted adjacent to the endof the transmission tube 38 which is opposed to the end thereof whichcarries the inner sleeve 23, and these ballbearings carry a toothedwheel or annulus 40 having inner teeth meshing with a set of planetpinions 41; as shown in Figure 5, these planet pinions are also inmeshing engagement with a sun wheel 42 rigid with the relevant end ofthe transmission tube 38. The toothed wheel 40 is also formed with aperipheral or outer set of teeth so as to constitute a worm-wheel for apurpose to be described presently.

Another toothed annulus 43 having the same set of teeth as the inner setcarried by the toothed wheel 40 is clamped in a fixed position betweenthe half-shells 28, 29 so as to be held against rotation. Another sunwheel 44 is keyed on the main shaft 16 adjacent to the end opposed tothat carrying the rolling-wheel 3. Between the toothed annulus 43 andsun wheel 44 a set of planet pinions 45 of same dimensions as theaforesaid planet pinions 41 are provided, as shown.

Each planet pinion 45 meshing with the toothed annulus 43 has a shaft45a co-axial to, and rotatably rigid with, another planet pinion 41meshing with the first-mentioned toothed annulus 40 and each shaft 45ais mounted for loose rotation in a needle-bearing 46 fitted in aplanetcarrier member 47 mounted in turn for free rotation on the mainshaft 16 through the medium of ball-bearings 48.

The main shaft 16 is driven from a motor through the intermediary of aclutch member 49 and a sleeve 52 constituting the hub of the sun wheel44 in the arrangement illustrated. Longitudinal stresses are supportedby a thrust bearing 51 and lateral stresses by a rollerbearing 53.

When the machine has been properly adjusted both toothed annuli 40 and43 are stationary.

Thus, the main driven shaft 16 is rigid with the innermost eccentricsleeve 23 through the sun wheel 44, the pair of planet pinions 41, 45,the sun wheel 42 and the transmission tubular shaft 38 so that themovement of rotation will be transmitted through these members from theclutch 49 to the rolling-wheel stub-shaft 13 and the eccentric sleeve 23fitted therearound. Consequently, these driven members 13 and 23 willrotate in the same direction and at the same angular velocity so as toconstantly remain in the same position relative to each other.

Obviously, this mechanism comprising toothed annuli, planet pinions andsunwheels would be useless if it were not required to alter the relativeangular positions of member parts 13 and 23. Thus, its only purpose isto enable the operator to change at will and to set within very finelimits the angular positions of these two parts. This is achievedthrough the angular displacement of the adjustable annulus 40 relativeto the stationary annulus 43 by means of a worm 50 meshing with outerteeth 65 of the annulus 40 and adapted to be actuated by hand even whenthe machine is running. This angular displacement does not interferewith the motion of the planet pinions which continue their rotationalmovement, but it brings about the relative angular displacement of mainshaft 16 and transmission tube 38.

Figure 6 of the drawings shows in longitudinal axial section thecarriage unit of the machine. A lower shaft 55 parallel to, and in thevertical plane of, the main shaft 16 carries a tubular worm 54 mountedfor axial sliding movement on this lower shaft 55 through a longitudinalkey 56 engaging a corresponding groove in worm 54 to prevent the latterfrom rotating about the shaft 55. Thus, the worm 54 and shaft 55 willrotate at the same angular velocity.

The lower shaft 55 is adapted, through the medium of the tubular worm54, to drive a pair of lateral worm wheels 57, 58 formed on verticalshafts 59, 60 having keyed or formed on their upper ends spur pinions61, 62, as shown. These spur pinions 61, 62 are in meshing engagementwith corresponding carriage-driving racks 63, 64.

With this arrangement, the carriage '83 is adapted to be driven alongthe axes of shafts 16 and 55 and to push the tubular article 1 to bebent by rolling, suitable means being interposed between the tubulararticle 1 and the carriage 83 for securing the former to the latter soas to prevent the tubular article 1 from rotating relative to thecarriage. The rate of feed of the carriage is set by means of thechange-speed gear which is a mechanism already known per se andtherefore requires no detailed description.

Figure 7 shows a complete view of the machine illustrating the greaterpart of its mechanisms in detail in order to facilitate theunderstanding of their relationship.

The frame structure of the machine comprises two separate sections. Therear half-frame structure 71 encloses the driving motor 72, thechange-speed gear contained in a case 73 and the transmission fordriving the planet pinions, together with the eccentric-adjustmentmechanism, these last-mentioned transmission and mechanism being bothenclosed in a common adjustment mechanism case 74 of which Figures 4 and5 show the constructional details.

Another, front half-frame structure 75 carries the smooth guide-membersor jaws 19, 20 receiving in sliding engagement the tubular article 1 tobe bent by rolling. These guide members also act as die means and areadapted to withstand the rolling stress produced by the machine throughthe rolling wheel 3. Moreover, this front half-frame structure 75 isprovided with a screw hoisting mechanism adapted to adjust the verticalposition of a wheel or roller 76 designed to guide the already bent tubeportion. This wheel or roller 76 is secured on a table 77 mounted forvertical sliding movement on the front half-frame structure 75. Thescrew hoisting mechanism provided for this purpose comprises a verticalscrew shaft 78 having keyed thereon a worm wheel 79 meshing with ahorizontal worm 80 adapted to be actuated by means of a hand crank 86.

Roller 76 is provided principally to permit the measuring of the radiusof bending of the tube. If, for example, it is desired to bend the tubewith a given radius, the level of table 77 is adjusted to acorresponding height and the position of the bent tube relative to saidroller indicates whether or not the tube is bent with the desiredradius. Thus, if the tube is not in contact with roller 76 as adjusted,the radius of the bend is too small. The roller 76 is not primarilyintended for bending the tube, but should the tube bear too heavily onsaid roller, the roller may have a small correcting effect by causing asmall reduction of the radius of the bend.

At any rate the radius of curvature cannot be reduced to a substantialdegree by means of this roller 76 alone, as the latter is intendedprimarily to keep the tubular article exactly in the plane of bending.Therefore, when the measurement of the radius of curvature has beenaccomplished, this roller 76 may be removed without any inconvenience;it is even preferable to remove it when frequent changes in the plane ofbending are to be effected.

Both half-frame structures 71, 75 are rigidly secured or embedded in theconcrete floor at an adequate distance from each other, according to themaximum length of the tubular articles to be bent.

To ensure a satisfactory and accurate operation of the machine, thelongitudinal axes of the various mechanisms constituting the machinemust be strictly parallel and aligned with one another. The properspacing between the half-frame structures 71 and 75 is provided andmaintained at their upper portions by the pair of carriagedriving racks63, 64 and at their lower portions by stiffening and spacing braces 81,82 the exact length of which should be adjusted accurately before thehalf-frame structures are definitely embedded in position so as toprovide the required parallelism.

The carriage 83 is slidably guided at its upper portion by the racks 63,64 and at its lower portion by the feed shaft 55, between the front andrear half-frame structures 71, 75.

The machine according to this invention is characterized by thefollowing substantial improvements:

(i) Various adjustments can be carried out during the operation of themachine, notably the adjustment of the degree of eccentricity or throwof the rolling-wheel axis relative to the axis of the tubular article tobe bent, this adjustment being effected by actuating the handwheel 84controlling the worm 37, as shown in detail in Figure 4;

(ii) Adjustment of the rolling radius by means of the handwheel 85 rigidwith worm 50 driving the annulus 40 of the planetary gear shown inFigure 4;

(iii) Adjustment of the radius of curvature of the tubular article to bebent, by means of the crank 86 rigid with worm 80;

(iv) The cooperating guide members 19, 20 can be tightened during theoperation of the machine for adjusting the length of the arc to berolled; this type of adjustment already described in the aforesaidFrench patent application may be combined with the adjustment affordedby the arrangement of this invention;

(v) These various adjustments may be combined in accordance with thisinvention for changing at will the radius of curvature or bending of thetubular article, without stopping the machine;

(vi) With the machine according to this invention it is also possible toalter the plane of bending at will. On the other hand, an 8 may beformed in a tubular article without removing the latter from themachine. Besides, the plane of bending may be altered to the desiredangular value by simply unclamping the tube on the carriage 83 andlowering (or even removing completely, if necessary) the table 77carrying the roller 76, and subsequently rotating the tubular article tothe desired angular extent, for example when it is contemplated to bendit to an S shape, and clamping the tube again on the carriage beforere-starting the machine.

While the above description refers to a specific embodiment of a tubebending machine constructed in accordance with the teachings of thisinvention, it will be readily apparent to anybody conversant with theart that many modifications may be brought thereto without departingfrom the spirit and scope of the invention as pointed out in theappended claims.

What I claim is:

l. A machine for bending a tubular article through a cold-rollingoperation comprising supporting guide members for receiving the tubulararticle therethrough, a driven shaft positioned for extending in thebore of said tubular article, a guiding mandrel for supporting one endof said shaft positioned between said guide members, a rolling wheelhaving a diameter smaller than the inner diameter of said tubulararticle and being mounted for loose rotation on said shaft about an axisoffset relative to the axis of said tubular article for contacting andthinning said tubular article in the region of its outer are of bendingthereby causing said article to bend, means for adjusting the positionof said driven shaft and means extending through said tubular articleand drivingly op erating said shaft adjusting means for on the one handaltering the throw between the axis of rotation of said shaft and theaxis of said tubular article and on the other hand between said axis ofrotation of said shaft and the axis of rotation of said rolling wheel.

2. A machine according to claim 1, including means for adjusting theaxis of said rolling wheel relative to the axis of said tubular article,and separate means for adjusting the position of said rolling wheel axisrelative to the axis of the surface of said article contacted by saidrolling wheel.

3. A machine according to claim 1 wherein said adjusting means includesan eccentric sleeve member having its bore in engagement with saiddriven shaft and adapted to rotate therewith at the same angularvelocity after the mutual angular positions of said shaft and saideccentric sleeve have been properly adjusted for altering the distancebetween said rolling wheel axis and the axis of the surface of saidtubular article contacted by said rolling wheel.

4. A machine according to claim 1 wherein said adjusting means includesan eccentric sleeve positioned between said driven shaft and saidmandrel for modifying the distance between said rolling wheel axis andthe axis of the surface of said tubular article contacted by saidrolling wheel, a tubular transmission shaft mounted on said driven shaftand carrying said eccentric sleeve member, a sun wheel rigidly mountedon said tubular transmission shaft, pinions in meshed engagement withsaid sun wheel, a planetary gear operatively connected with saidpinions, a toothed annulus in driving connection with said planetarygear and means provided for rotating said annulus and thereby rotatingsaid sleeve for adjusting the position of said rolling wheel axis.

5. A machine according to claim 1 wherein said adjusting means includesan eccentric sleeve positioned between said driven shaft and saidmandrel for modifying the distance between said rolling wheel axis andthe axis of the surface of said tubular article contacted by saidrolling wheel, a tubular transmission shaft mounted on said driven shaftand carrying said eccentric sleeve member, a sun wheel rigidly mountedon said tubular trans mission shaft, a planet carrier member mounted onsaid driven shaft for free rotation thereon, a set of pinions in meshedengagement with said sun wheel, a plurality of shafts each fixedlyconnected to one of said pinions and mounted on said planet carriermember for free rotation thereon, a second set of pinions each fixedlymounted on one of said shafts with a pinion of said first mentioned set,a second sun wheel fixedly mounted on said driven shaft, a fixedlytoothed annulus having said second set of pinions in meshed engagementtherewith whereby said driven shaft and said sleeve will rotate in thesame direction and at the same angular velocity and means provided forrotating said first mentioned set of pinions for changing the positionof said sleeve relative to said driven shaft.

6. A machine according to claim 1 wherein said adjusting means includesan eccentric sleeve member mounted on said rolling wheel driving shaftand adapted to rotate therewith at the same angular velocity, a secondeccentric sleeve member, a bearing having said first mentioned sleeverotatably mounted therein, the outer race of said bearing being providedby the bore of said second sleeve, a third eccentric sleeve surroundingsaid second sleeve, means for rotating said second and third sleeveswhen desired for adjusting the relative throw of said axis of rotationof said shaft and said tube axis and means for changing the relativeangular position of said first mentioned sleeve and said driven shaftmodifying the throw between said shaft axis of rotation and the axis ofrotation of said rolling wheel.

7. A machine according to claim 1 wherein said adjusting means includesan eccentric sleeve member mounted on said rolling wheel driving shaftand adapted to rotate therewith at the same angular velocity, a secondeccentric sleeve member, a bearing having said first mentioned sleeverotatably mounted therein, the outer race of said bearing being providedby the bore of said second sleeve, a third eccentric sleeve surroundingsaid second sleeve, a pair of concentric tubular transmission shaftscarrying at one end said second and third eccentric sleeve respectively,a pair of parallel and aligned bevel wheels each rigid with one of saidpair of tubular shafts, a bevel pinion having its axis at right anglesto said wheels and meshing therewith for imparting angular displacementof the same value but opposite directions to said bevel wheels andtherefore said second and third sleeve members for adjusting therelative throw of said axis of rotation of said shaft and said tube axisand means for changing the relative angular position of said firstmentioned sleeve and said driven shaft modifying the throw between saidshaft axis of rotation and the axis of rotation of said rolling wheel.

8. A machine according to claim 1 wherein a presser roller is mountedadjacent said mandrel on the article emerging side thereof and adaptedto co-act with and support the convex portion of the bend in saidarticle and means are provided for adjusting the position of saidroller.

No references cited.

